Mark BL31 initialization functions

Mark the initialization functions in BL31, such as context management,
EHF, RAS and PSCI as __init so that they can be reclaimed by the
platform when no longer needed

Change-Id: I7446aeee3dde8950b0f410cb766b7a2312c20130
Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
diff --git a/lib/el3_runtime/aarch64/context_mgmt.c b/lib/el3_runtime/aarch64/context_mgmt.c
index ee5fe4f..acc8d6d 100644
--- a/lib/el3_runtime/aarch64/context_mgmt.c
+++ b/lib/el3_runtime/aarch64/context_mgmt.c
@@ -36,7 +36,7 @@
  * which will used for programming an entry into a lower EL. The same context
  * will used to save state upon exception entry from that EL.
  ******************************************************************************/
-void cm_init(void)
+void __init cm_init(void)
 {
 	/*
 	 * The context management library has only global data to intialize, but